1,544 research outputs found

    Differences in prefrontal blood oxygenation during an acute multitasking stressor in ecstasy polydrug users

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    Background: Cognitive deficits are well documented in ecstasy (MDMA) users with such deficits being taken as evidence of dysregulation of the 5HT system. More recently neuroimaging has been used to corroborate these deficits. The present study aimed to assess multitasking performance in ecstasy polydrug users, polydrug users and drug naïve individuals. It was predicted that ecstasy polydrug users would perform worse than nonusers on the behavioural measure and this would be supported by difference in cortical blood oxygenation. Methods: Twenty ecstasy-polydrug users, 17 polydrug users and 19 drug naïve individuals took part. On day 1 drug use history was taken and questionnaire measures were completed. On day 2, participants completed a 20 minute multitasking stressor while brain blood oxygenation was measured using functional near infrared spectroscopy (fNIRS). Results: There were no significant differences between the 3 groups on the subscales of the multitasking stressor. In addition, there were no significant differences on self-report measures of perceived workload (NASA – TLX). In terms of mood, ecstasy users were significantly less calm and less relaxed compared to drug-naïve controls. There were also significant differences at 3 voxels on the fNIRS indicating decreased blood oxygenation in ecstasy users compared to drug naïve controls at V2 (left DLPFC), V14 and V16 (right DLPFC), and compared to polydrug controls at V14. Conclusions: The results of the present study provide support for changes in brain activation during performance of demanding tasks in ecstasy polydrug users, which could be related to cerebral vasoconstriction

    Electrophysiological Evidence of Atypical Processing Underlying Mental Set Shifting in Ecstasy Polydrug and Polydrug Users

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    Executive functioning deficits are reported in ecstasy users. However research into mental set switching has been equivocal, with behavioural studies suggesting the function is preserved. The current study sought to address the issue of switching deficits in ecstasy users by combining behavioural performance with electrophysiological correlates (EEG). Twenty ecstasy polydrug users, 20 non-ecstasy polydrug users and 20 drug naive controls were recruited. Participants completed questionnaires about their drug use, sleep quality, fluid intelligence and current mood state. Each participant completed a mental set switching task (the number-letter task) whilst EEG measures were recorded. ANOVA revealed no between group differences on performance of the task, however a regression suggested that ecstasy use was a significant predictor for performance, after controlling for cannabis use. Mixed ANOVA revealed a significant effect of group on the P3, with significant differences between both drug groups and naives. There was also an interaction between electrode and group on the P2 component, with ecstasy users differing from both other groups. On the P3 component the results suggest a reduction in positivity at parieto-occipital electrodes for drug users compared to controls. Furthermore a significant increase in negativity in ecstasy users compared to control groups could be observed in several occipito-parietal electrodes at an N2 component as well as observable atypicalities in early processing (P2) displayed by ecstasy users and polydrug controls. The present study provides evidence of atypical processing of attentional shifting in ecstasy and polydrug users. Deficits in this executive function could reflect cognitive inflexibility and paucity of rapid behavioural adjustment, which may be problematic in real world situations. Keywords: Ecstasy; cannabis; executive function; stimulants; cannabis

    Prayer, personality and happiness: a study among undergraduate students in Wales

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    In order to examine the association between prayer and happiness, a sample of 131 undergraduate students attending a university in Wales completed three measures: the Oxford Happiness Questionnaire, the abbreviated Eysenck Personality Questionnaire Revised, and prayer frequency assessed on a 5-point scale. The data demonstrated a significant positive correlation between prayer frequency and happiness before controlling for individual differences in personality. After controlling for personality, however, this apparent association vanished

    Does hypoxia play a role in the development of sarcopenia in humans? Mechanistic insights from the Caudwell Xtreme Everest Expedition

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    OBJECTIVES: Sarcopenia refers to the involuntary loss of skeletal muscle and is a predictor of physical disability/mortality. Its pathogenesis is poorly understood, although roles for altered hypoxic signaling, oxidative stress, adipokines and inflammatory mediators have been suggested. Sarcopenia also occurs upon exposure to the hypoxia of high altitude. Using data from the Caudwell Xtreme Everest expedition we therefore sought to analyze the extent of hypoxia-induced body composition changes and identify putative pathways associated with fat-free mass (FFM) and fat mass (FM) loss. METHODS: After baseline testing in London (75m), 24 investigators ascended from Kathmandu (1300m) to Everest base camp (EBC 5300m) over 13 days. Fourteen investigators climbed above EBC, eight of whom reached the summit (8848m). Assessments were conducted at baseline, during ascent and after one, six and eight week(s) of arrival at EBC. Changes in body composition (FM, FFM, total body water, intra- and extra-cellular water) were measured by bioelectrical impedance. Biomarkers of nitric oxide and oxidative stress were measured together with adipokines, inflammatory, metabolic and vascular markers. RESULTS: Participants lost a substantial, but variable, amount of body weight (7.3±4.9kg by expedition end; p<0.001). A progressive loss of both FM and FFM was observed, and after eight weeks, the proportion of FFM loss was 48% greater than FM loss (p<0.008). Changes in protein carbonyls (p<0.001) were associated with a decline in FM whereas 4-hydroxynonenal (p<0.001) and IL-6 (p<0.001) correlated with FFM loss. GLP-1 (r=-0.45, p<0.001) and nitrite (r=-0.29, p<0.001) concentration changes were associated with FFM loss. In a multivariate model, GLP-1, insulin and nitrite were significant predictors of FFM loss while protein carbonyls were predicted FM loss. CONCLUSIONS: The putative role of GLP-1 and nitrite as mediators of the effects of hypoxia on FFM is an intriguing finding. If confirmed, nutritional and pharmacological interventions targeting these pathways may offer new avenues for prevention and treatment of sarcopenia

    Methyl iodide poisoning presenting as a mimic of acute stroke: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>Stroke mimics are usually non-vascular disease processes. These raise the possibility of a stroke and are common in clinical practice. It is necessary to distinguish these mimics in order to provide early and appropriate management, as well as reduce possible harm on our patient.</p> <p>Case presentation</p> <p>We report the case of a 50-year-old Caucasian man who developed symptoms suggestive of posterior circulation stroke after he was exposed to methyl iodide at his workplace. Results of stroke investigations of our patient were negative, and a detailed occupational history clinched the diagnosis. Acute presentation with a stroke-like picture is rare in cases of methyl iodide poisoning. We have attempted to discuss the differential diagnosis of stroke mimics through a review of literature.</p> <p>Conclusion</p> <p>Stroke mimics are difficult to diagnose in an emergency room situation and may be initially treated as stroke. This case report underlines the importance of history taking, especially occupational history, in the differential diagnosis of stroke. We also stress the need to recognize mimics at presentation in order to arrive at an early and appropriate management of patients.</p

    Static stretching of the hamstring muscle for injury prevention in football codes: a systematic review

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    Purpose: Hamstring injuries are common among football players. There is still disagreement regarding prevention. The aim of this review is to determine whether static stretching reduces hamstring injuries in football codes. Methods: A systematic literature search was conducted on the online databases PubMed, PEDro, Cochrane, Web of Science, Bisp and Clinical Trial register. Study results were presented descriptively and the quality of the studies assessed were based on Cochrane’s ‘risk of bias’ tool. Results: The review identified 35 studies, including four analysis studies. These studies show deficiencies in the quality of study designs. Conclusion: The study protocols are varied in terms of the length of intervention and follow-up. No RCT studies are available, however, RCT studies should be conducted in the near future

    Statistical modeling of ground motion relations for seismic hazard analysis

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    We introduce a new approach for ground motion relations (GMR) in the probabilistic seismic hazard analysis (PSHA), being influenced by the extreme value theory of mathematical statistics. Therein, we understand a GMR as a random function. We derive mathematically the principle of area-equivalence; wherein two alternative GMRs have an equivalent influence on the hazard if these GMRs have equivalent area functions. This includes local biases. An interpretation of the difference between these GMRs (an actual and a modeled one) as a random component leads to a general overestimation of residual variance and hazard. Beside this, we discuss important aspects of classical approaches and discover discrepancies with the state of the art of stochastics and statistics (model selection and significance, test of distribution assumptions, extreme value statistics). We criticize especially the assumption of logarithmic normally distributed residuals of maxima like the peak ground acceleration (PGA). The natural distribution of its individual random component (equivalent to exp(epsilon_0) of Joyner and Boore 1993) is the generalized extreme value. We show by numerical researches that the actual distribution can be hidden and a wrong distribution assumption can influence the PSHA negatively as the negligence of area equivalence does. Finally, we suggest an estimation concept for GMRs of PSHA with a regression-free variance estimation of the individual random component. We demonstrate the advantages of event-specific GMRs by analyzing data sets from the PEER strong motion database and estimate event-specific GMRs. Therein, the majority of the best models base on an anisotropic point source approach. The residual variance of logarithmized PGA is significantly smaller than in previous models. We validate the estimations for the event with the largest sample by empirical area functions. etc

    The self-reported Montgomery-Åsberg depression rating scale is a useful evaluative tool in major depressive disorder

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    Abstract Background The use of Patient-reported Outcomes (PROs) as secondary endpoints in the development of new antidepressants has grown in recent years. The objective of this study was to assess the psychometric properties of the 9-item, patient-administered version of the Montgomery-Åsberg Depression Rating Scale (MADRS-S). Methods Data from a multicentre, double-blind, 8-week, randomised controlled trial of 278 outpatients diagnosed with Major Depressive Disorder were used to evaluate the validity, reliability and sensitivity to change of the MADRS-S using psychometric methods. A Receiver Operating Characteristic (ROC) curve was plotted to identify the most appropriate threshold to define perceived remission. Results No missing values were found at the item level, indicating good acceptability of the scale. The construct validity was satisfactory: all items contributed to a common underlying concept, as expected. The correlation between MADRS-S and physicians' MADRS was moderate (r = 0.54, p Conclusion Taking account of patient's perceptions of the severity of their own symptoms along with the psychometric properties of the MADRS-S enable its use for evaluative purposes in the development of new antidepressant drugs.</p

    The AIB1 glutamine repeat polymorphism is not associated with risk of breast cancer before age 40 years in Australian women

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    INTRODUCTION: AIB1, located at 20q12, is a member of the steroid hormone coactivator family. It contains a glutamine repeat (CAG/CAA) polymorphism at its carboxyl-terminal region that may alter the transcriptional activation of the receptor and affect susceptibility to breast cancer through altered sensitivity to hormones. METHODS: We evaluated this repeat polymorphism in the context of early-onset disease by conducting a case-control study of 432 Australian women diagnosed with breast cancer before the age of 40 years and 393 population-based control individuals who were frequency matched for age. Genotyping was performed using a scanning laser fluorescence imager. RESULTS: There were no differences in genotype frequencies between cases and control individuals, or between cases categorized by family history or by BRCA1 and BRCA2 germline mutation status. There was no evidence that the presence of one or two alleles of 26 glutamine repeats or fewer was associated with breast cancer (odds ratio = 1.03, 95% confidence interval = 0.73–1.44), or that women with alleles greater than 29 repeats were at increased risk of breast cancer. Exclusion of women who carried a BRCA1 or BRCA2 mutation (24 cases) and non-Caucasian women (44 cases) did not alter the risk estimates or inferences. We present raw data, including that on mutation carriers, to allow pooling with other studies. CONCLUSION: There was no evidence that risk of breast cancer depends on AIB1 CAG/CAA polymorphism status, even if affected women carry a mutation in BRCA1 or BRCA2
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